Preparing high-temperature lubricating greases



Nov. 20, 1951 VA. J. MORWAY ET AL 2,576,033

PREPARING HIGH-TEMPERATURE LUBRICATING GREASES Filed Dec. 17, 1949 EFFEOT OF COOILINO TEMPERATURES ON FURFURAL 'GQEASES (10% F'URFURAL. BEFORE IZEAOTION) Av EQAGE. COOKING TEMPERATURE -F',

(3m 13 550 30 P: 40.0 [LL K0 Ex. 1 o 88 EJLI O 550 DQQPPING 0 D pomr Z 2 mm 4150 S W PENETRATION AFTER 9 100,000 Smokes V 2 g 4OO a a g 250- 3 9 550 Q r. U 5 200- k 0 o L] DENETQATION AFTER z 50 STIzOILas (l l l Cl III :1 .01 o 2 A fl CLtborneg molecular weight substances.

metal base greases. cases at least, improve the physical structure of lubricating greases and are particularly useful in stabilizing them structurally at elevated tem- Patented Nov. 20, 1951 UNITED STATES PATENT OFFICE PREPARING HIGH-TEMPERATURE LUBRICATING GREASES Arnold J. Morway, Rahway, and John J. Kolfenbach, Somerville, N. J., assignors to Standard Oil Development Company, a corporation of Delaware Application December 1'7, 1949, Serial No. 133,542

11 Claims. 1 i I The present invention relates to a process for preparing high temperature lubricating greases and relates particularly to a process involving the use of low molecular weight salts of cyclic acids combined with conventional soaps as thickening metal base to produce the metal salt of the corresponding carboxylic acid as a grease com- "ponent. The application discloses the use of furiural, as a specific aldehyde, and indicates that other cyclic and especially heterocyclic aldehydes may be used.

It has previously been suggested in the prior art, that for some purposes it is advantageous to combine certain metal salts of relatively low molecular weight with the metal soaps ordinarily "employed as thickeners for lubricating grease compositions. There appear to be a number of opinions as to the effect of such combination of ingredients, but various investigators have found that the addition of metal salts of relatively low molecular weight organic acids has some utility in grease compositions.

Some have suggested that the addition of the low molecular weight acid compounds to the relatively high molecular weight soaps results in the formation of a complex of salt and soap, with superior grease thickening effect and of improved stability, for example, at elevated temperatures. on the other hand, it may be that the provision of a lower organic salt to be used with the soap tends to offset a normal tendency of some of the soaps of certain of the higher fatty acids, especially the more unsaturated acids, to break down into lower It is probable that the equilibrium existing in the soaps is shifted somewhat by the addition of these lower molecular weight materials. a 1

Whatever may be the phenomena involved, the addition of salts, and the like, of relatively low molecular weight compounds appears to be advantageous, especially in alkali and alkaline earth These materials, in many stable. Greases which include these low molecular weight salts appear to be quite susceptible,

also, to further stabilization by conventional oxidation inhibitors.

Although various low molecular weight compounds have been proposed recently, such as the salts of acetic and propionic acids and certain of the lower unsaturated acids, such as acrylic and crotonic acid, and the like, as being particularly useful as grease modifiers, these acids are not always suitable and the more desirable of them are rather expensive.

According to the invention described in the aforesaid application, the aldehydes which are treated with strong alkali undergo the well known Cannizzaro reaction. According to the Cannizzaro reaction principle, an aldehyde having an alpha carbon atom free of hydrogen may be treated with a strongly alkaline material to oxidize one molecule of such aldehyde to an acid radical at the expense of an adjacent molecule which is converted to the alcohol. Thus, an aldehyde of the general formula RnC-CHO, where R may be any organic substituent, is treated with strongly alkaline material, resulting in converting half of the aldehyde into the corresponding alcohol and the other half into the corresponding carboxylic acid.

The acid formed in the Cannizzaro reaction is neutralized immediately to form the salt while the alcohol is formed simultaneously. The latter may be removed by evaporation or it may be esterified to a degree by acidic materials which may be present. The alcohol, if unsaturated, may polymerize or it may undergo side reactions of various sorts.

The combination of the salt formed in the Cannizzaro reaction and the conventional soap of fatty acids or other fatty materials serves as the thickening or bodying agent which gives the composition its grease structure.

Furfuraldehyde, commonly referred to as furfural,is abundantly available and quite inexpensive, being a by-product of certain of the cereal grain industries such as the oatmeal industry.

It is recoverable in large quantities by the sulfuric acid treatment of materials containing 'pentosans, such as corn cobs, oat hulls, bran, and

the like. The Cannizzaro reaction, as applied to furfural, proceeds as follows:

3 The resulting products are respectively the sodium salt of furoic acid (pyromucic acid) and furfuryl alcohol. Other analogous aldehydes are equally useful and react similarly. Among these are the homologous aldehydes and their thio derivatives, and also benzaldehyde and its close homologues. i. e. those of 5-membered heterocyclic ring type, are particularly preferred.

The metal salt of the cyclic or heterocyclic acid and the corresponding alcohol may be produced during an ordinary grease-forming reaction by adding the alkaline material in suitable quantities to a hydrocarbon oil containing the aldehyde to cause the Cannizzaro reaction to proceed. At the same time, or subsequently, the

The furan-type aldehydes normal soap of C12 to C22 fatty material may be prepared by saponifyingsuch fatty acids with a suitable base. Preferably, the aldehyde .and the alkali are reacted first in the presence of some part of the lubricating oil. The use of some of the oil, which is chemically inert, helps to reduce the violence of the reaction, which is exothermic, and thereby assists in controlling the temperature. The fatty acids to be saponified are added later, together with additional alkali,

if required. The remainder of the lubricating oil, which'forms the liquid element of the grease,

preferably is added last.

The use of salts of relatively low molecular weight cyclic organic acids, such as furoic acid,

is not to be confused with the use of related esters having entirely different purposes. Thus, in the Zimmer and Morway U. S. Patent No.

2,113,754, granted April 12,1938, there is dis closed the use of certain esters, including some .furoic acid esters, as oiliness agents in various materials including both lubricating oil and lubricating greases. The esters used, however, are entirely different from the salts employed in the present instance, and their function is not related in any way to the function of the furoic acid salts and their equivalents.

' Thus a grease may be prepared from a lubricating oil (preferably a mineral base oil at least in part, though synthetic oils of the ester or glycol type may be used in part when not present during saponification, etc.), a high molecular weight fatty material of at least 12 and preferably 14 or 16 to about 22 carbon atoms, a saponifying agent, and the salt derived through the Cannizzaro reaction.

The relative proportions of the high molecular Weight soaps and the low molecular weight salts,

prepared from aldehydes as indicated above, may be varied rather widely. .Broadly, molecular proportions of about 1 to 4 parts of soap. may be used with about 1 to 4 parts of the salt. In general, however, it, is preferable that the molecular proportions be more nearly equal and molar proportions of about 1 to. 1 or 1 to 2 are usually preferred. The total quantity of these ingredients .to be used in a given grease composition will vary depending upon thev type of grease desired. For

a. very stiff grease, the proportions of total 'thi'c'keners may approach 50% total whereas about -2 to of the metal salt of the low mol r weight heterocyclic' carboxylic acid.

Narrower limits of 5 to 25% soap and 3 to 15% of salt are usually adequate. Starting materials may comprise about 2 or 3 to 25 parts by weight of aldehyde, 3 to 30 parts of fatty material and to 96 parts of oil, with conventional or theoretical proportion of alkali or saponifying agents.

With regard to the relative proportions of high molecular weight soaps and low molecular weight salts, it appears that a fairly high molar ratio of salt to soap is desirable where the soap content of the finished grease is 15% or more by weight. When the soap content is less, the salt content should be reduced more than proportionally. Thus, when these greases were prepared with relatively large concentrations of soap (15% or more) the combination giving about the best grease structure and lubricating performance was a ratio of about lop-arts of fur fural (converted of course to the furoic acid salt with alcohol by-product) to 15 parts of hydrogenated fish oil acids (to be converted to soap) or a ratio of 2:3 by weight of these ingredients.

The combination of a conven-tional metal soap of fatty materials and the salt obtained through the Cannizzaro reaction, forms a stable grease of good high temperature properties, provided certainrequirements for cooking temperature and mechanical working during processing are filled. The furaldehyde or analogous furan type or other aldehyde may be added directly as'such ,or it may. be introduced as an ingredient directly from a solvent treating process for oils wherein one or more efiluent streams contain furfural,

for example. As set forth in another copending' application by one of the present inventors, Serial No. 60,616, now Patent No. 2,516,138, also filed November 17, I948, the use of such materials simplifies the process in some cases and renders unnecessary certain convention steps for recovering the solvent furfural, removing it from treated oils and/or aqueous fluids involved. in

conventional solvent treating techniques. The

.present invention is applicable in certain fespects to. the process set forth and claimed in said application Serial No. 60,616. I

In the aforesaid processes, the presence and the recovery or removal of the furfuryl or related alcohol give rise to certain difiiculties under some conditions. Furfuryl alcohol, for example, has

the'formula b3 C-CHOH with two insaturated bonds. It has a strong tendency" to polymerize at elevated temperatures and has also a relatively low flash point which gives rise to some hazards in processes involving high temperatures in the presence of air or oxygen. The thioaldehyde merely substitutes sulfur for the oxygen in the ring and behaves similarly. i

In the processes described in copending applications Serial Nos. 60,615 and 60,616, now Patents Nos. 2,516,137 and 2,516,138, ascarried out atfirst, it was the practice. toapply a fairly high degree of heat during the soap formation to" cook" the grease, evaporate the water, and drive ofi the alcohol, or most of it, resulting from the Cannizzaro reaction. While such heating, is not' impracticable, though subject to certain hazards because thealcohols have a low fia-shpoint, temperatures above about: 410 It, even spot temperatures. cause objectionable polymerization of the alcohols and other side reactions, to form thermosetting resins and other oil insoluble and non-lubricating bodies in the grease. These detract considerably from the lubricating value of the grease, especially for long-life lubrication of antifriction bearings, though they do not render it useless for some less critical requirements.

For the lubrication of anti-friction bearings, it appears that a satisfactory grease should retain its grease structure after severe mechanical working and should also hav a consistency after moderate working of not less than about 230 and not more than'about 300 mm./ penetration (after 60 strokes in the standard ASTM grease worker). It should have good high temperature performance. Such greases can be obtained, according to the present invention, by (1) proper control of cooking temperature and (2) proper working during manufacture.

The use of a conventional fireheated grease kettle for preparing greases Where the Cannizzaro reaction is involved is objectionable for several reasons. The uneven heating of the kettle is hazardous because of the flash point of the alcohols which are produced. The same lack of uniformity tends to promote the polymerization and perhaps other undesirable side reactions of unsaturated alcohols to an unacceptable degree. While greases of satisfactory structure can be made at lower temperatures in small batches where they can be worked vigorously (to obtain'maximum dispersion of the salts and soaps) such effective mechanical working is not feasible in large batches.

In order to avoid these difficulties it is preferred to use a steam heated kettle where temperatures are normally more uniform and can be more accurately controlled. Unfortunately, steam pressures available at most oil refineries and greasemaking plants are not in excess of about 125 p. s. i. Hence available temperatures are not above about 340 F., and are frequently much lower. Steam kettles are available, then, only for cooking temperatures of about 290 to 340 F. or at most about 350 F., and higher cooking temperatures must be obtained in other ways. in the neighborhood of 300 F. are not satisfactory for, greases of the type under consideration in several respects. They do not cook the grease adequately for high temperature performance. They are inadequate to evaporate the water quickly.

so that long cooking is required with undesirable degradation in color. They do not remove the alcohol by-products of the Cannizzaro reaction as effectively as is desired.

It appears to be necessary, therefore, to reach a temperature, of the range of 360 to 410 F., preferably about 380 to 400 F., to avoid the foregoing objections. This can be done in the following manner with the beneficial results indicated in the examples which follow.

The Cannizzaro reaction ingredients are first placed in a portion only of the lubricating oil. The reaction is carried out at a moderate temperature, e. g. between room temperature and about 200 F. or so, preferably between about 100 and 150 F. The presence of the oil, preferably 30 to 60% of the total oil to be used in the grease, tempers'the reaction and assists in controlling the reaction temperature within desired limits.

After the Cannizzaro reaction has been substantially completed, the fatty saponifiable material is added, the saponifying agent, usually as an Temperatures aqueous solution or slurry, is introduced. and the temperature is raised to form the soap in the oil. The ingredients should be stirred during the entire process, at least up to the cooking stage. If desired the soap may be formed simultaneously with the Cannizzaro reaction step, but since the latter preferably takes place at a lower temperature it normally is carried out first and this is the preferred procedure.

After the steam kettle hasbeen heated up to its maximum temperature, the remaining to 7 0% of the lubricating oil is introduced at a higher temperature. This oil may be separately heated in any suitable manner, preferably to a temperature between about 400 and 475 F. The heated oil, of course, raises the temperature of the batch, effectively completes the cooking of the soap and the evaporation of residualmoisture in a minimum of time, and accomplishes all this without materially enhancing the fire or explosion hazard.

The steam kettle of course is not indispensable, as a moderately heated fire kettle maybe used, or other heating means may beemployed. It is important, however, to have uniform heating and to avoid hot spots which degrade the ingredients and add to the hazards mentioned.

Ordinarily the reactant materials will be heated up to the maximum safe or available temperatureof 300 to 340 F. or so, and then the separately heated oil introduced while further moderate heating is continued. Where heating means are available, the final cooking may be carried on to temperatures as high as 500 F. but this 3 should not be done until and unless the alcohol Cannizzaro reaction and for the saponification of the C12 to C22 fatty acids or other fatty material, the product resulting from this process has excellent high temperature properties and also has good moisture resistance, which is not typical of ordinary soda base greases. At the same time the quantities of soap and salt required for a grease of a given consistency are minimized. Since the salt derived through the Cannizzaro reaction from the aldehyde replaces part of the soap normally required for a grease of a given consistency, the process results in considerabl economy.

Good products may be made using KOH as the reactant in the Cannizzaro reaction and/or in the soap formation: The potassium greases have a somewhat lower dropping point than those of soda base, but still have good high temperature performance. Their water resistance is somewhat poorer than that of the soda greases. The potassium greases, on the average, have a softer consistency.

Obviously NaOH may be used for the Cannizzaro reaction and KOH for the saponification or vice versa. Other saponification agents may be used in combination with 01- in lieu of the alkali metal hydroxides to prepare various types of greases but the strong alkaline bases are preferably used for the Cannizzaro reaction.

The aldehyde used may be selected from the cyclic aldehydes of 4 or 5 to about 10 carbon atoms, especially the heterocyclic compounds such as furfural, thiophene aldehyde and the like, and also benzaldehyde, and its immediate EXAMPLE I ingredients zgg gfig Cannizzaro Reaction:

Fiu'fural; .1 10.00 Sodium Hydroxide. 3.18 Mineral Oil 10.00 Hydroiol Acids-54 (Hydrogenated fish oil acids of dominantly low 20 carbon atoms) 15. Sodiumliiyoroxide 2. 00 Phenyl alpha naphtliylamlne Mineral Oil (about 55 S. S. U. viscosity at 210 lr Thefurfural and asmall portion of the min-' eral (amount shown in the Cannizzaro reaction portion of the above formulations) is charged to a grease, kettle and stirring initiated. A 33 /372; cold aqueous solution of part of the sodium hydroxide is then added. The temperature rises to about. 185 F. and the reaction is continued until the temperature drops to about 90 F. \usually in about one hour). The Hydrofol Acids 54 are then charged to the kettle and saponified with the balance of the sodium hydroxide and the temperature raised to'300 F. The balance of the oil is slowly added and the temperature is raised to 450 F. The phenyl alpha naphthylamine or equivalent anti-oxidant is added and after its incorporation the grease is cooled preferably inpans. greaseis homogenized by kettle working to a smooth, uniform, oily product. The product of Example I showed the following properties:

Per cent free alkalinity, 0.02% as NaOI-I ASTM Worked penetration (range of penetration obtained with this method of manufacture),

150-200 mm./ Dropping point, F., above 500 F.

Removal of a portion of the sodium furoate formed in the Cannizzaro reaction showed the dried and ether washed soap to be dark in color and apparently some ether insoluble polymeric material is absorbed on the soap. The appearance of the finished grease was dark brown in color.

EXAMPLE II Cannizzaro reaction: 10.00% Furfural 3.18% NaOH 30.00% Mineral oil 15.00% Hydrofol acids 54 2.00% NaOI-I 1.00 Phenyl alpha naphthylarnine 38.82 Mineral oil as in Example I The grease was prepared similar to the method described in Example I, except the Cannizzaro reaction was run in 30% mineral oil (based on the weight of the total composition) and the top temperature of the reaction was only 14-4 F. A portion of the sodium furoate when dried and ether washed was a light pinkish color with no dark material present indicating very little resin formation. Thegrease was finished by cooking On cooling the 8 V V at 400F. .Inapp'earance the-finished. grease was light tan incolor. 1

ASTM worked penetration, 265 mm./ 10 Dropping point, F., above 500 1 soften the grease, without materially affecting the dropping point.

' EXAMPLE III Further studies on the production of furfural grease, of the general type of Examples I and II, indicates that products having excellent-bearing lubrication life can be prepared in the steam jacketed kettle, followed by milling Q Where available steam pressures did not provide tern peratures materially aboveabou't 300" F., there sulting product was found to lack stability under conditions of severe mechanical working. *By preparing a concentrate of the salt and soapforrning ingredients in only a part of the lubricating oil, preferably to and-ad'ding'the remainder of the oil which is heated to higher temperature than steam limitations permit, a product of excellent stability is produced. Thus 3 to 25 parts by weight of the aldehydemay be combined at first with aboutl5. to 55 parts-of oil and later 3 to 30 parts of fatty material will be added. Finally, about 20 to aditional parts of oil which is hotter are added.

The degree of mechanical working during preparation of the salt (Cannizzaro reaction product) and of the soap also appears to have a marked effect on the structure stabilityand high speed spindle life the grease. Small pilot plant batches cooked at steam kettle temperatures; as

formation was practicable than is possible'witl'i larger batches. With full production'batches large kettles, the same high degree o f-workirig is not feasible and apparently a higher cooking temperature becomes requisite if a grease of firm consistency after severe working is to be secured. Full steam kettle batch prepared at a temperature of 338 F., showed poor consistency, i. e. penetration above 400 mn1./10 after 100,000 strokes in the A. S. T. M. grease worker employing a fine-hole plate. A batch prepared in a fire heated. kettle at 450 F. (with attendant hazards, as mentioned above) showed excellent consistency after 100,000 strokes (276 mm./ 10 penetrationas corn?- pared with cover 400 for the steam kettle batches) and gave a spindle life test of 838 hours. 'A laboratory. batch, prepared with controlled mechanical.

' data are shown in the attached drawing. Itwill .grease was high in all cases.

be noted that the dropping point of the soda TABLE I Pilot plant production-of furfural grease 1 Temperature varied in difi'erent portions of kettle contents be cause of poor agitation.

3 Fire kettle pilot plant production.

EXAMPLE IV In the preferred method and according to the present invention, furfural is used in proportions of 5 to by weight of the total ingredients. This is placed in part of the mineral oil and the strongly basic reactant, NaOH is introduced to cause the Cannizzaro reaction to take place.

Thereafter the fatty material is saponified' Saponification is carried out at the maximum cooking temperature permitted by the steam kettle-usualy not more than 340 F. and frequently around 300 F. Hot oil, e. g., at a temperature of 450 F., is introduced with continuous stirring, to complete the cooking. This gives a higher temperature than the usual steam facilities permit, avoids the hazards mentioned above, and has the additional advantage of making a long cooking period unnecessary. Lon cooking results in color degradation and high evaporation losses which this method eliminates.

The following data show comparative stability of compositions having similar ingredients but prepared by the different methods.

1 Employing fine hole worker plate, 325 Lie holes.

1 5% I'm-fora], 7.5% hydrofol acids 54, 2.5% N e011, 1% phenyl alpha naphthylamine, 84% Biol 55.

5 10% lurfural, otherwise like (2).

This method (using separately heated oil to achieve a higher cooking temperature than steam permits) is especially valuable in the production of greases having low soap content. Suchgreases are more critically dependent upon the maximum utilization of soap. They also are more easily and effectively stirred as the hot oil is in troduced.

Greases prepared by this method may be improved in appearance by passing them through milling rolls or through a homogenizer such as a Lancaster disperser after they have cooled to a fairly low temperature, e.'-g. below about 100 F.

weight of KOH was used in lieu of 3.18% NaO'H In general, 5 to 10 parts of furfural with 30 to 50 parts of oil are treated with theoretical proportions of NaOH. Thereafter 15 parts. of-fatty material are added and saponified and 40 to parts of hot oil added last. These are preferred proportions within the wider limits mentioned elsewhere.

EXAMPLE V A grease was prepared using 10% by weight of furfural, 3.18% of NaOH, and 30% mineral oil (of about 40 SSU viscosity at 210 F.). The remainder (about 39%) of mineral oil was held for heating and introduction later. The NaOH and furfural were reacted in the oil to produce the furoic acid salt, after which 15% of hydrogenated fish oil acids (Hydrofol Acids 54) and 1.80% NaOH were added to make the soap. This mixture was cooked in the steam jacketed kettle and then the balance of the mineral oil (of SSU viscosity at 210 F.) was introduced (at a temperature of about 450 F.) into the kettle which was heated by a steam jacket p. s. 1., about 340 F.). After the soap was thus further cooked, accompanied always by continuous mixing to obtain thorough dispersion of salt and soap, the anti-oxidant (1% phenyl alpha naph thylamine) was added and the product was cooled in conventional cooling pans. The prop.- erties are shown in Table III.

EXAMPLE VI Example V was repeated except that 4.4% by for the Cannizzaroreaction. The product was somewhat softer and showed a higher water solubility. Its dropping point was 426 F., as compared with a dropping point above 500 F. for the straight sodium base grease. 2% sodium hydroxide was used to saponify the fatty acids. Results are tabulated in Table III. Both greases hardened somewhat on the severe mechanical working.

EXAMPLE VII I In this example, 2.25% by weight ofKOI-I and 1.59% of NaOI-I were used for the Canizzaro reaction, instead of the straight KOH of Example VI. The grease was of consistency intermediate between Examples V and VI but had a slightly lower dropping point than Example VI, of 418 F. See Table III.

EXAMPLE VIII In this example the same ingredients as in Examples V, VI and VII were used, except that 0.45% of KOI-I by weight, based on the total composition, and 2.87% of NaOH were used for the initial Cannizzaro reaction. The consistency was slightly better than that of Example VII and the dropping point was 460 F.

EXAMPLE IX This composition was prepared like Examplev, except that 1.50% NaOH and 0.50% of lime, by weight, were used to saponify the hydrogenated fish oil acids, resulting in a mixed base sodalime grease. It had a firm consistency, excellent water resistance, and good high temperature properties. See Table III.

' 500 'F. was attained.

TABLE III Formulation (Per Cent Weight) Example V Example VI Example VII Example VIII Example IX 'Cannizzaro Reaction 10.00 10. 10. 00 V 2.25 0; 45 1. 59 2. 87 3.18 0 30. 00 30. 00 30. O0 0 V 15.00 15.00 15. 00 O 2.0 2.00 2.00 1. 50 Phenyl Alpha Naphthylamine 1. 00 1.0 1.00 1.00 1. 00 Mineral ()il 70 SSU Visc. at 210 F 39.02 37. 0 38.10 38. 68 38. 82

Properties Penetrations, mm./

60 strokes worked 200 328 288 281 205 100,000 strokes worked 1 285 200 280 240 223 Per Cent Free Alkalinity NaOH 0. 47 0. 3 0.1 0. 55 0. 62 Dropping Point, F...- 500+ 426 418 460 470 Water Solubility 0 at 77 F. 0 at 125, F. Per Cent Loss 3 0 at 125 F. 100 at 77 F. 100 at 125 F. 27 at 125,F. 10 at 150 F. 10,000 R. P. M. Spindle Test at 300 F.,

' Hours I, 120 No data I 511 No data 490 1 Example IX also contained 0.5% lime. 1 325 hole Ms diameter worker plate. 1 AN- (3-15 method.

- Na-Oa grease clings to wet surface (displaces water) while Na grease will not stick to wet metal suriace.

It has been suggested above that lubricating oils other than those of mineral base may be used, at least in part, in preparing greases according to this invention. In some synthetic oils, or compositions containing them, His not feasible to carry out the Cannizzaro reaction because the alkali would produce undesirable side reactions such as hydrolysis. In such compositions the Cannizzaro reaction, and the saponification also, may be carri'ed out in a small amount of mineral oil, after which oils of other type may be added; This presupposes, of course, that the nonmineral oils are compatible with the mineral oil. Proportions of to 30 parts by weight of mineral oil, 30 to 70 parts of synthetic or non inineral oil, 5 to 15 parts .of the non-volatile products of the Cannizzaro reaction, and 10 to parts of soap are preferred.

EXAMPLE X A compositionwas prepared with the following starting materials:

Per cent by Weight Furfural 10.0 NaOH 3.2 Mineral oil, 55 S. S. U. at 20 F 20.0

Hydrogenated fish oil acids (Hydrofol 51 HO) 15.0 NaOH 2.0 Di-2-ethyl hexyl sebacate 49.2

' additional 2.0% NaOH, also as a aqueous solution. The mixture was heated with continuous stirring until the soap was formed and the moisture evaporated. Heating was further continued until a temperature of 450 F. was reached. The

's'yntheic 'esterwas then added gradually and heating was continued until a temperature of This was done to assure a full and complete dispersion of the soap and the sodium furoate. The productwas cooled in a 1-inch layer and became a black, slightly grainy mixture. After working down to a grease consistency it had the following properties;

Original penetration, mm./ 10 150 stroke penetration, mm./10 180 1000 stroke, fine hole plate, mm./10 I 265 Dropping point 'F 420 Wheel bearing test, 6 hrs. at 250 F Excellent Other esters, polyglycols, silicone oils and the like. may be used in the same manner andin vari.- ous mixtures. Conventional additives maybe included. Heating for cooking the soap should be at least to 380 FL, and 450 F. or even higher may be desirable, provided care 'is taken to remove the alcohol in such amanner as to avoid fire and explosion hazards. The final further heating to 500 F. or so seems to improve the high temperature properties.

Obviously, conventional modifiers such as oiliness agents, extreme pressure additives, metal deactivators, tackiness agents, oxidation and corrosion inhibitors, andthe like may be added in usual proportions without substantial variation 7 from the invention.

What is claimed is:

1. Process which comprises adding :3 to 25 parts by weight of a heterocyclic aldehyde having no alpha hydrogen and having a 5-membered heterocyclic ring to 15 to ,55 parts ,of -mineral lubricating oil, adding an alkali metal base to form the Cannizzaro reaction products in said oil, forming 3 to 30 parts of-soap of C1: to C22 fatty material in said oil, cooking to a temperature of 290 to 350 'F., and thereafter adding 20 to parts of lubricating oil at a-temperature of 400 to 475 F. to complete the cooking and form. a high temperature structure stable lubricating grease. I

2. Process as in claim 1 wherein said aldehyde is furfural'.

3. Process as in claim 1 wherein said aldehyde is thiophene aldehyde. i V

'4. Process as in claim 1 wherein said aldehyde is benzaldehyde.

5. The process of preparing a lubricating grease which comprises adding 2 to 25parts by Weight of 'furfural "to 30 't0--5'5 parts of mineral base lubricating oil, adding sufficient alkali'metal hydroxide; vto convert said furfural to. the correalcohol, forming 3 to 30 parts of soap 01' fatty material in the C12 to C22 range in said oil, cooking to a temperature within the range of about 290 to 350 F., and thereafter adding 40 to 65 parts of additional lubricating oil at a temperature in excess of 400 F. to raise the final temperature, complete the cooking and elimination of volatile constituents, and improve the high temperature properties and the structure stability of said grease.

6. Process as in claim 5 wherein the alkali metal hydroxide is NaOH.

7. Process as in claim 5 wherein the alkali metal hydroxide is KOH.

8. The process which consists essentially in adding 5 to parts by weight of furfural to 30 to 50 parts of mineral base lubricating oil, adding enough alkali metal hydroxide to convert said furfural, through the Cannizzaro reaction, to the corresponding metal furoate and furfuryl alcohol, maintaining the temperature between room temperature and 200 F. during such conversion, thereafter adding 5 to parts of substantially saturated fatty acids having an average chain length of about 16 to 20 carbon atoms, adding a metal base saponifying agent selected from the class consisting of alkali and alkaline earth metal bases and mixtures thereof and cooking to a temperature range between about 290 and 350 F. to form a soap in situ in said 011, along with said metal furoate, thereafter introducing about 40 to 60 parts of additional mineral lubricating oil at a temperature of the range of 400 to 475 F. to further cook said soap and associated the REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,700,056 James Jan. 22, 1929 2,108,643 Brunstrum Feb. 15, 1936 2,113,754 Zimmer Apr. 12, 1938 2,182,137 Rioketts Dec. 5, 1939 2,409,950 Meyer Oct. 25, 1946 2,441,720 Roehner et a1 May 5, 1948 2,449,312 Murray Sept. 14, 1948 2,450,221 Ashburn et a1. Sept. 28, 1948 2,455,982 Fraser Dec. 7, 1948 2,516,136 Morway et al. July 25, 1950 2,516,137 Morway et a1 July 25, 1950 OTHER REFERENCES Organic Chemistry, Fieser and Fieser, P38. 217 and 549. 

1. PROCESS WHICH COMPRISES ADDING 3 TO 25 PARTS BY WEIGHT OF HETEROCYCLIC ALDEHYDE HAVING NO ALPHA HYDROGEN AND HAVING A 5-MEMBERED HETEROCYCLIC RING TO 15 TO 55 PARTS OF MINERAL LUBRICATING OIL, ADDING AN ALKALI METAL BASE TO FORM THE CANNIZZARO REACTION PRODUCTS IN SAID OIL, FORMING 3 TO 30 PARTS OF SOAP OF C12 TO C22 FATTY MATERIAL IN SAID OIL, COOKING TO A TEMPERATURE OF 290 TO 350* F., AND THEREAFTER ADDING 20 TO 65 PARTS OF LUBRICATING OIL AT A TEMPERATURE OF 400* TO 475* F. TO COMPLETE THE COOKING AND FORM 